In recent years, the incidence of cardiovascular disease has increased. According to the investigation made by the World Health Organization, at present, cardiovascular diseases account for about 30% of all diseases, and are expected to account for 40% of all diseases in 2020. Most of the cardiovascular diseases ultimately affect the function of the left ventricle, resulting in diseases affecting the function of the left ventricle, such as left ventricular failure, and cardiogenic shock.
In view of diseases affecting the function of the left ventricle, domestic and foreign scholars propose new methods. Left ventricular assist devices (abbreviated as LVAD) are used for patients with left ventricular dysfunction to drain blood in the left ventricle into the aorta, to provide a circulatory support. The LVAD can be divided into an implantable LVAD and a body-side LVAD according to whether the LVAD is implanted in the body, and can be divided into a pulsatile LVAD and an axial-flow LVAD according to the flow form of blood.
A traditional left ventricular assist device is implanted by surgical procedures. A passage is established between the left ventricle and the aorta by perforating the left ventricle and the aorta and arranging a pump between them.
Surgical implantation will cause a large operation wound. At present, the most commonly used percutaneous left ventricular assist devices in clinic applications mainly include an Extracorporeal membrane oxygenation (abbreviated as Ecmo) system, an intra-aortic balloon counter pulsation (abbreviated as IABP), a Tandem Heart percutaneous left ventricular assist device and an Impella ventricular assist system. In the Ecmo system, two cannulas are implanted into the aorta and the main vein respectively, the cannula in the main vein is connected to an external artificial lung, and the external artificial lung is connected to the cannula in the aorta via an axial-flow pump or a pulsatile pump. The disadvantage of the Ecmo system is that the external artificial lung is required, which causes complex structure and interruption of pulmonary circulation, and thus it is apt to cause pulmonary intravascular thrombosis and massive hemorrhage. In the intra-aortic balloon counter pulsation, a long balloon is inserted into the aorta, and the balloon is inflated and deflated with the beating of the heart to increase the myocardial blood supply. The disadvantage of the intra-aortic balloon counter pulsation is that it depends on the function of the ventricle, and thus its operation is not stable. The Tandem Heart system is comprised of an inflow cannula punctured into the left atrium via the femoral vein, an extracorporeal central pump and an outflow cannula punctured into the left ventricle via the femoral artery, thus a drainage channel is established from the left atrium to the femoral artery. The disadvantages of the Tandem Heart system are that there are two large wounds, the operation is complicated and an atrial septal puncture is required. The Impella system is comprised of a cannula punctured into the left ventricle via the femoral artery, a cage-shaped blood inlet is provided at a front end of the cannula, a blood outlet is provided at the ascending aorta, and an axial pump is provided between the inlet and the outlet to drain blood in the left ventricle into the aorta. The disadvantage of the Impella system is that the flow depends on a rotating speed of the pump, and blades rotating in high speed may damage red blood cells and so on.
In conclusion, an issue to be addressed by the person skilled in the art is to solve the problems, under the premise of achieving the left ventricle assisting function, that the existing left ventricular assist device has a complex structure, is complicated to operate, and may cause large wounds to human tissue cells, and the operation thereof is unstable.